Prescribed nondegenerate high-order modes in an axial-asymmetric high-finesse Fabry-Perot microcavity

We report an axial-asymmetric high-Q Fabry-Perot cavity supporting nondegenerate Hermite-Gaussian modes of the same mode order. Axial asymmetry of mirror surface was introduced by mechanically grinding off one side of a cylindrical mirror substrate without degrading the original mirror quality. The bases of the resulting Hermite-Gaussian modes were aligned with respect to the direction of grinding, making it possible to prescribe the mirror principal axes.